Deinonychus

Concept art of Mark "Crash" McCreery for Jurassic Park of Deinonychus, which would later be renamed to Velociraptor later in the film's production.

Deinonychus was the first of the raptors (technically called "Dromaeosaurs") to be known from a nearly complete skeleton. Velociraptor had been discovered forty years earlier but was known only from a skull and a few bones of its hands and feet.

The skeleton of Deinonychus were first to show the now infamous sickle-shaped retractable foot claw (8 inch), used for ripping open the skin of a victim, causing the preys guts be ripped and with a considerable amount of damage. Deinonychus also had a nasty bite, with over 60 knife-like teeth. Although with a deadly bite its arms and legs would be most powerful and could rear on one leg and kick an opponent.

Dr. John Ostrom discovered Deinonychus in 1964. Dr. Ostrom believed that this dinosaur was an agile, swift predator, more like a warm-blooded mammal or bird than a cold-blooded crocodile.

In the video game The Lost World: Jurassic Park Deinonychus is an enemy in various levels. It bears a resemblance to the Velociraptor that appeared in the game as well, only different in colors. Oddly, it's a bit smaller than the Velociraptor, instead of being bigger. In the game they're also called "Deinon-Raptor", likely to differentiate them from the Veloci-Raptors.They are grey and have yellow spots.

Deinonychus was the basis for novel canon's Velociraptors and in turn the raptors seen in the films.

Jurassic Park novel author Michael Crichton visited John Ostrom—the discoverer of Deinonychus—when doing research for the novel. Ostrom said that Crichton's Velociraptor was based on Deinonychus in "almost every detail" and Crichton had even called him to inform him that he had renamed the Deinonychus in his novel to Velociraptor because he felt it sounded "more dramatic".

During the production of the Jurassic Park film, Steven Spielberg's production contacted John Ostrom and requested copies of all the technical papers that Ostrom had done of Deinonychus. Unlike the novel, the raptors seen in the film were to be properly named Deinonychus and Mark "Crash" McCreery had even made concept art of this raptor in 1991. But later in pre-production it was renamed to Velociraptor like in the novel and McCreery's concept art was later attributed to the newly named dromaeosaur.